fix: Filament v5 callbacks $r → $record (Plans/Subs/SuperAdmins/Companies)

+ central PWA: real PNG icons, SW registration, scope=/

- All `fn ($r) =>` and `fn (Type $r) =>` replaced with $record (Filament v5
  injects callback params by name; $r resolved to nothing)
- /pwa/admin-{192,512}.png — generated on-the-fly with GD + DejaVuSans-Bold
- /pwa/admin-icon.svg — vector favicon
- /admin-sw.js — service worker (cache shell, network-first elsewhere)
  with Service-Worker-Allowed: / header
- Manifest scope=/ + start_url=/admin → install prompt fires on Chrome/Edge/Safari
- BODY_END render hook registers SW on central panel

app/Filament/Central/Resources/PlanResource.php

@@ -88,11 +88,11 @@ class PlanResource extends Resource
             ->columns([
                 Tables\Columns\TextColumn::make('name')->searchable()->sortable(),
                 Tables\Columns\TextColumn::make('price_monthly')
-                    ->money(fn ($r) => $r->currency)
+                    ->money(fn ($record) => $record->currency)
                     ->label('Lunar')
                     ->sortable(),
                 Tables\Columns\TextColumn::make('price_yearly')
-                    ->money(fn ($r) => $r->currency)
+                    ->money(fn ($record) => $record->currency)
                     ->label('Anual'),
                 Tables\Columns\TextColumn::make('companies_count')
                     ->counts('companies')